Given two positive integers L and R, the task is to count the elements from the range [L, R] whose prime factors are only 2 and 3.
Input: L = 1, R = 10
2 = 2
3 = 3
4 = 2 * 2
6 = 2 * 3
8 = 2 * 2 * 2
9 = 3 * 3
Input: L = 100, R = 200
Approach: Start a loop from L to R and for every element num:
- While num is divisible by 2, divide it by 2.
- While num is divisible by 3, divide it by 3.
- If num = 1 then increment the count as num has only 2 and 3 as its prime factors.
Print the count in the end.
Below is the implementation of the above approach:
- Count numbers from range whose prime factors are only 2 and 3 using Arrays | Set 2
- Count numbers in a range having GCD of powers of prime factors equal to 1
- K-Primes (Numbers with k prime factors) in a range
- Find and Count total factors of co-prime A or B in a given range 1 to N
- Count common prime factors of two numbers
- Count all prime numbers in a given range whose sum of digits is also prime
- Print all numbers whose set of prime factors is a subset of the set of the prime factors of X
- Numbers in range [L, R] such that the count of their divisors is both even and prime
- Sum of numbers in a range [L, R] whose count of divisors is prime
- Count of natural numbers in range [L, R] which are relatively prime with N
- Count of Double Prime numbers in a given range L to R
- Count Numbers in Range with difference between Sum of digits at even and odd positions as Prime
- Queries for the difference between the count of composite and prime numbers in a given range
- Common prime factors of two numbers
- Sum of all even factors of numbers in the range [l, r]
- Sum of all odd factors of numbers in the range [l, r]
- Find sum of exponents of prime factors of numbers 1 to N
- Count of Nodes whose both immediate children are its prime factors
- Count occurrences of a prime number in the prime factorization of every element from the given range
- Number of distinct prime factors of first n natural numbers
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.